The present invention relates generally to techniques for sampling subsurface substances. Specifically, the invention focuses both methods and apparatus for soil chemistry sampling which do not substantially disturb the environment to be sampled.
The concept of chemically sampling a subsurface substance such as soil, biological products (fungi, bacteria, flora, etc.), water content, or other substances has been known for many years. Through the general technique, a subsurface location is accessed and then sampled in order to ascertain its chemical characteristics. These characteristics can include a great variety of attributes including but not limited to the substance chemical makeup, its moisture content, and the like.
One of the challenges which those skilled in the art have faced is the fact that the sampling action itself can impact both the immediate test results as well as the subsurface character. Not only has this resulted in the sampling action itself being closely scrutinized, but it has also caused those skilled in the art to often question results achieved. This is especially true when attempting repetitive sampling for chemical composition at the same point. In such applications, the technique, prior to the present invention, has often been to physically retrieve a small portion of the subsurface substance and to then analyze that retrieved material.
Naturally, in any retrieval of a substance, that substance is disturbed. In spite of this almost obvious aspect, some have characterized such test methodology as a methodology which does not disturb the subsurface substance. This characterization alone may have served to lead those skilled in the art away from the direction taken by the present invention. The present invention significantly overcomes the limitations that those skilled in the art have faced as a result of such techniques; it achieve substantially undisturbed testing of subsurface chemistry.
Perhaps surprisingly, the present invention discloses both methods and apparatus which overcome these limitations through very simple means. This may in part be due to the fact that while those skilled in the art had recognized a long-felt need for the results which the present invention achieves, they had not fully appreciated the nature of the problem. In fact, to some degree those skilled in the art may have even taught away from the direction taken by the present invention. By focusing upon testing or sampling at different locations rather than at different times at the same location they may have also been directed away from the present invention. Although those skilled in the art have in other aspects improved sample acquisition systems, to a large part their efforts have been directed more towards sample systems which retrieve small portions of the substance rather then sample systems which did not substantially disturb the substance. For instance U.S. Pat. No. 5,101,917 to Abdul represents an improvement in a soil retrieval assembly. Unlike the present invention it clearly disturbs the soil it is retrieving. Other art has been directed to other fields, such as root growth and the like; these are not applicable as they do not deal with the unique problems of chemistry sampling where actual contact can be necessary but where even small impacts from such contact can have significant effects on the present and future state of the point sampled.
To some degree, those skilled in the art may even have failed to recognize that by achieving substantially undisturbed sampling, time dependent sampling could replace sampling at different locations within a particular subsurface. To the extent those skilled in the art directed their efforts to more complex sampling systems, they also may have failed to realize the efficiencies with which a simple device could achieve repetitive sampling. Thus, the simplicity with which the present invention achieves solutions to the problems which had existed may have also contributed to leading those skilled in the art away from the direction taken.